It seems on my side, it's fine, after you upgrade the new firmware , have you tired to reset and reconfigure it? You can also try to sue good cable , Cat5e cable is recommended.

Switch to another phone and try again, and you need connect to your main router's wifi first and then go to settings to connect to tplinksmartplug wifi and then try to add the device.

if that happens, how can you make it work again? Just wait for a while and then it will automatically recover? Since it says no internet connection, are you sure by that time if the camera is online？

Check Antivirus altert history, is anything related being blocked? Try disable Antivirus. Can you still ping the camera from your phone or computer when you cannot access internally? To further...

Devices like your computer, thermostat will not leak password. They are your own devices. You can trust them. As for those unknown devices, you can block them.

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